The ability of many microorganisms to produce extracellular polymers is well known. Of particular interest are some heteropolysaccharides because of their unique viscosity and rheology properties. Most notable among this group of polymers is xanthan gum which is produced by strains of the bacterial genus Xanthomonas. Xanthan gum has proven to be useful for a variety of applications. Examples include as a food additive (see U.S. Pat. Nos. 3,519,434; 3,557,016; 3,692,541; 3,726,690), as a stabilizing agent, friction reducing agent, or suspending agent in the petroleum industry (see U.S. Pat. Nos. 3,305,016; 3,319,715; 3,618,664), as a suspending agent for paints and starch (see U.S. Pat. Nos. 3,481,889; 3,692,552), and as a gelling agent for explosives, detergents, and sanitizers (see U.S. Pat. Nos. 3,326,733; 3,655,579; 3,741,805). These examples are only illustrative of the many uses of xanthan gum and are not meant to be exhaustive. Other uses can be found in the literature.
Other heteropolysaccharides produced by organisms other than Xanthomonas have been found to have properties and uses similar to that of xantham gum. U.S. Pat. No. 3,933,788 discloses a heteropolysaccharide produced by Klebsiella pneumoniae (originally classified as Erwina tahitica) and U.S. Pat. No. 4,329,448 discloses a heteropolysaccharide produced by Bacillus polymyxa.
The present invention discloses a novel heteropolysaccharide which can be produced by several known bacteria as well as a novel bacterium of the species Enterobacter sakazakii. The polymer of the present invention has unique viscoelastic properties and is superior to known heteropolysaccharides such as xanthan gum in its ability to reduce the frictional drag of fluids.